Lyme Disease Flashcards
what do the chemical secretions a tick secrete facilitate
feeding
- one blocks sensation of pain
- one blocks sensation of irritation
acute irritant reactions may occur with tick
- what look like
- when develop
- when resolve
Red welt or itchy raised lesion
develops after tick falls off
resolves in 48 hours
acute irritant reactions may occur with tick
- what look like
- when develop
- when resolve
Red welt or itchy raised lesion
develops after tick falls off
resolves in 48 hours
Management of a tick bite (3)
ice or cool compress
oral analgesics or antihistamines
close monitoring for s/sx of lyme disease x 30 days
how long should you monitor for signs of lymes disease after a tick bite
30 days
criteria for acquiring lyme disease from tick bite (2)
1) patient must have been bitten by a tick that is infected with B. burdorferi
2) the tick must have been attached for at least 24 hours
when criteria for acquiring lyme disease are met what is risk of developing lyme disease
less than 4%
sources of data lyme disease surveillance
active and passive tick monitoring
-documented infections are underestimation due to undetected or unreported cases
West canada tick with lyme disease
western blacklegged tick
- ixodes pacificus
eastern canada tick that can carry lyme disease
blacklegged tick
-Ixodes scapularis
Lyme diesease risk areas
- how often check risk of practice area
annually
- PHAC interactive Map
- detailed map from provincial health authorities
Can lyme disease be found outside documented areas?
yest, tciks can travel with their hosts
determination of duration of tick attachment
when last in at-risk area
degree of tick engorgement
what do you do if patient unsure how long tick attached
consider attached 24 hours
what type of ticks cary lyme disease
only black legged ticks transmit lyme disease
what changes in ticks after feeding
colour, size, shape
what does most of feeding adult of nymph
nymphs do most of feeding because they are smaller and harder to find
PEP
post exposure prophylaxis
PEP in children younger than 12yrs pregnant or lactating, evidence of active lyme disease
- what drug/dose
- endpoint/time period
doxycycline 200mg x 1 dose
0.4% incidence (relative to 3.2% placebo) of (endpoint) development of erythema migrans at site of tick bite (at 3wks and 6wks)
Doxycycline
- what type of drug
- what schedule
tetracycline antibiotic
available by Rx only
doxycycline dosage forms (2)
- what is only available through special access program
oral tablets and capsules
-IV formulation only available through special access program
doxycycline drug interactions (3)
oral anticoagulants
hepatic enzyme inducers
isotretinoin
doxycycline MoA
-what consideration/counsil point
binds to divalent cations (ex. Ca, Fe)
forms non-absorbable complex
- wait 2hrs before/after dosing doxy with Ca and Fe (and other divalent cation) supplements
doxycycline AEs (5)
allergy superinfection photosensitivity N/V esophagitis and esophageal ulcer
doxycycline: notes on AEs
- photosensitivity
- esophagitis and esophageal ulcer
Photosensitivity
- high risk of LD is sumer, photosensitivity risk, causes redening of skin
esophagitis and esophageal ulcer
- only if take for a long time
are patients at risk of doxycycline AEs for LD treatment
for single dose (as in LD treatment) most of the AEs are not issues
most ppl tolerate doxycycline well
doxycycline in kids
- CPS (what trimesters/nursing/children)
bc tetracyclines can bind Ca2+ in developing bones or teeth, CPS cautions use in
- pregnancy esp in 2nd and 3rd trimester
- long term use in nursing people (dose 1X for LD)
- children less than 8 years of age
doxycycline of all tetracyclines, what is doxycycline’s binding efficiency
less strong than most
doxycycline in children AAP
- use in children
- how many days
**how many doses for LD
doxycycline can be given to children of any age for durations less than 21 days
Should you give doxycycline to children
use AAP
- give it to children
- counsel parents on potential risks
pharmacist prescribing for LD, important consideration for referral
this is an urgent issue, do not refer unnecessarily
RPh Rx’ing for LD PEP, 3 steps
1) confirm eligibility for PEP
2) rule out contraindications
3) Rx doxycycline 200mg po x 1 dose
1) confirm eligibility for PEP (4)
- documented tick bite acquired in at risk area
- tick attached at least 24 hours (or engorged)
- tick removed within past 72 hours
+ longer? may have missed window for PEP - no evidence of active LD
signs of active LD
rash or bruise, fever, headache
2) rule out contraindications (2)
Allergy
SOGC suggests PEP can be considered during pregnancy
3) Rx doxycycline 200mg po x 1 dose
- what about in children
in children
- 4mg/kg po x 1 dose (maximum 200mg)
child dose of doxycycline
4mg/kg/dose
doxycycline maximum dose in children
200mg
implementation and follow up: for ALL patients regardless of PEP or not (3)
counsel on tick bite avoidance
advise to monitor for lyme disease symptoms for 30 days
notify primary care provider to ensure appropriate follow-up
how long should patients monitor for lyme disease symptoms
30 days
implementation and follow up: patients not qualifying for PEP
reassure low risk for infection
- likelyhood of infection increases with attachment time
Urgent referral
any patient with symptoms suggestive of LD
what avoids progression to disseminated disease
early tx
in order to develop LD:
patient must have B. brudorferi-infected tick attached for at least 24 hours
doxycycline PEP effectiveness
87% effective at preventing clinical LD
statement on doxycycline in pregnancy
although historically contraindicated, current evidence suggests that children and pregnant ppl can be offered doxycycline PEP
